CuO nanorods growth on folded Cu foil as integrated electrodes with high areal capacity for flexible Li-ion batteries

Abstract

Although the conventional slurry-coated electrodes are successful in various batteries, they do not suit for flexible electrodes based energy storage because the active materials tend to detach from the current collector during bending. Besides, the electrochemical performance of slurry-coated electrodes always declines dramatically with increasing mass loading, resulting in limited areal capacity (∼3.5 mA h cm−2 or less). Herein, we develop a series of CuO nanorods/folded Cu foil integrated electrodes with high mass loading and areal capacity for flexible energy storage. CuO nanorods grow directly on Cu foil, not only restraining the exfoliation of CuO from Cu substrate under bending but also facilitating electron transport. By using a folding design, the integrated electrode (four folds) can reach CuO loading of 15.2 mg cm−2 and deliver a high areal capacity of 13.95 mA h cm−2 at the first discharge. Using these CuO/Cu integrated electrodes as anodes, we construct flexible Li-ion full cells, exhibiting excellent electrochemical performance and superior mechanical strength of anodes.